Cellulose derivatives such as carboxymethylcellulose, methylcellulose, methylethylcellulose, hydroxypropylmethylcellulose and hydroxypropylcellulose are non-caloric (non-metabolizable by humans or intestinal flora in human beings), odorless, tasteless water-soluble polymers derived from cellulose. These cellulose derivatives may act as thickeners, binders, stabilizers, suspending agents or flow control agents. They form films resistant to oils, greases and organic solvents. They dissolve rapidly in cold and hot water and are physiologically inert. In theory, the non-caloric nature of cellulose derivatives would suggest that they might be used as filler materials or substitutes for fat, sugar, carbohydrate or other high calorie components of normal food products. However, the simple substitution of such non-toxic non-caloric substances for a high calorie food component, is not practicable because any substantial substitution of a normal food ingredient will typically alter one or more of the color, volume, texture, structure, mouthfeel, odor or flavor of the food to such an extent as to render the food product unacceptable to a consumer.
Degradation of cellulose derivatives is normally considered undesirable and to be avoided. Cellulolytic and viscosity reducing treatments on cellulose derivatives have been deliberately avoided in the past and high molecular weight products deliberately produced. Indeed, non-degraded cellulose derivatives have been incorporated into food stuff compositions as disclosed in U.S. Pat. No. 4,214,009 to Chang.
Enzymatic hydrolysis of cellulose derivatives have been studied in the past in the context of synergism studies among combinations of enzymes, the possible indexing of substituent distribution patterns, the effect of various substituents on enzymatic hydrolysis and the like. Such studies have been published in the following: Chouchon et al., Biotech. Bioeng., Vol. 26, pp. 988-991 (1984); Henrissat et al., Biotechnology, Vol. 3, pp. 722-726 (1985); Chetkarov et al., Monatshefte Fur Chemie, Vol. 116, pp. 1433-45 (1985); Chetkarov et al., Monatshefte Fur Chemie, Vol. 117, pp. 1021-1026 (1986); Wirick, J. Polym. Sci., Part A-1, Vol. 6, pp. 1195-1974 (1968); Bhattacharjee, J. Polym. Sci., Part C, Vol. 36, pp. 509-521 (1971). Reduction of chain length have also been studied. Almin et al., Arch. Biochem. Biophys., pp. 124, 129 (1968); Ghose, Biotech. Bioeng., Vol. 11, pp. 239 (1969).
Numerous studies throughout the world have shown a link between a fatty diet high in cholesterol, and heart diseases. Also, because of its high energy content (about 9 kcalories/g) high fat consumption may cause obesity and its associated problems. It is recommended (by e.g. The American Heart Association) that fat consumption should be reduced so that no more than 30% of caloric energy is derived from fat. It also has been recommended that an increased proportion of calorie intake should be obtained from complex carbohydrates rather than fat. Fat in the diet should thus be partially omitted or substituted. However, fat endows desirable eating qualities (e.g. taste, mouthfeel, aroma, consistency) and consumers are used to and enjoy the properties that fat lends to food. So substitution of fat with a non-fat substance that is fat-free but has fatty consistency and mouthfeel would be an attractive approach to this problem.
The production of different types of starch derivatives has been described, e.g. in Radley, J. A. Starch And Its Derivatives, 4 ed. [p. 382] 1968 and in Rutenberg et al., Starch: Chemistry and Technology, 2ed., pp. 311-88 (1984). Derivatives such as oxidized starches, cross-linked starches, starch ethers and cationic starches are discussed in the foregoing. One or more of the inventors herein have also shown the production and use of higher molecular weight polysaccharides, including starch and cellulose derivatives, in a variety of different applications in U.S. Pat. Nos. 4,810,646; 4,851,393; 4,749,620; 4,744,933; 4,739,693; 4,732,205; 4,119,783; 4,666,492.
Carboxymethyl starch (CM starch) is an ether type starch derivative typically prepared by the reaction of chloroacetic acid on starch in the presence of alkali. The sodium salt of CM starch, which occurs also under the name sodium starch glycolate, is used as a disintegrant in pharmaceutical tablets. Other proposed or actual usages are, e.g. components of absorbents, adhesives, medical poultices, thickening agents, stabilizers, papermaking, coating and pulp refining. CM amylose has been suggested to be used to lower the blood sugar level or as blood volume expander. It has been used as a substrate when studying the kinetics of amylases. CM starch is insoluble in cold water, but it has high water absorption properties such that CM starch particles swell to several times their original volume.
Maltodextrin, enzymatically hydrolysed starches, are commercially available. However, these products are less preferable.
There are also some new developments in the area of low-calorie fat mimetics that have been recently approved or are awaiting regulatory approval. They have been made, e.g. by modifying natural proteins physically or by modifying sucrose chemically. However, many of these compounds have functional limitations.